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This print-layout has a "to thin" returnline for MAX power 3 Amp.

You have to make a better layout, or make it stronger with a 0.6 m.m. wire, extra, between the end-point.

A fine Lab. Supply, I have made 3 of them until now, working perfekt!!
Good luck.

3D_pcb_top_bottom.png

Edited by OZ6YM

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I am talking about this project http://www.electronics-lab.com/project/0-30v-laboratory-power-supply/
Look
at the PCB...
The return-line for MINUS or the GROUND-WIRE is to thin...
Make it bigger to take 3 Amp at 30 Volt.

That is my comment....
...what a guru...

I have never seen this defective new copy of the original project before. It has all the errors of the original project and added some new errors. The parts numbering has been changed so it is difficult to say that a resistor is 1/4W but must be 1W and its value should be xxx. Many parts are overloaded and the opamps have a total supply voltage too high for them.

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Hi,

Audioguru, would you mind point out where can I find the improved schematic of the Chinese (banggood) and  Greek power supply kit?

I have one of those kits and I would not mind expending few dollars to improve it ... or I may  have the components in the shack.

Thanks!

Edited by Mayoral

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Thank you very much! I see what you mean, it is not only changing few component.... I have almost every component I may make it next new project ! 

Since I was curious I was digging the forums and the web an I came across a very similar schematics. In this one, Q1, R13 and R14 have been included back to "mitigate transient surge issue". Since you look pretty knowledgeable (and my knowledge that does not go that far), do you have an opinion in this incorporation? Will it affect the overall performance of the supply?

Thanks in advance again for your time and comments.post-107142-14279144730853.thumb.gif.319

Edited by Mayoral

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I did not look into the transient that might occur when the power is turned on or off. Q1 was originally placed to short the output of opamp U2 because the old TL081 original opamps had a problem called "Opamp Phase Inversion" when an input voltage became too close to the negative supply voltage when the negative supply collapsed first when the power was turned off. It would have caused the output of the opamp U2 to suddenly go as high as it can which is bad for the speaker. The new opamps do not have this problem.

You can add Q1 and its resistors if you want.

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There is (or was) a Greek kit available and today there is a Chinese copy of the Greek kit. The kits have a pcb. If you use a kit then you can cross your fingers and hope that one of its many overloaded parts do not fail soon.

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On 2/15/2016 at 9:14 AM, Mayoral said:

Thank you very much! I see what you mean, it is not only changing few component.... I have almost every component I may make it next new project ! 

Since I was curious I was digging the forums and the web an I came across a very similar schematics. In this one, Q1, R13 and R14 have been included back to "mitigate transient surge issue". Since you look pretty knowledgeable (and my knowledge that does not go that far), do you have an opinion in this incorporation? Will it affect the overall performance of the supply?

Thanks in advance again for your time and comments.post-107142-14279144730853.thumb.gif.319

Sir, Is it ok if I use a 30V from the secondary output of a transformer or It must be a 24V secondary output.  Sorry I am new in understanding what a 28VAC transformer means.

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I can buy a transformer with any voltage that I want. A 28VAC one or a 30VAC one will work in this modified circuit and the circuit will have a maximum regulated output of 30VDC at 3A.

If you use a transformer that is 24VAC then the maximum regulated output from this modified circuit will be about 25VDC at 2.5A, and if the voltage and current controls are at maximum then the output will produce lots of unregulated ripple.

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